Field of the Invention
The invention is directed to an optical module and a head mounted display and more particularly, to an optical module and a head mounted display having an optical waveguide.
Description of Related Art
With the progress of display technologies and people's desire for high-tech, technologies with respect to virtual reality and augmented reality have become more and more mature. Among them, a head mounted display (HMD) that can achieve the technologies has drawn more and more attention in the display field.
FIG. 1A is a schematic diagram illustrating a head mounted display of the related art. FIG. 1B is a schematic enlarged diagram of a region AA depicted in FIG. 1A. Referring to FIG. 1A  FIG. 1B, a head mounted display 10 includes an optical waveguide 12, a plurality of beam splitters 14, a reflector 16 and a display device 18. The beam splitters 14 and the reflector 16 are disposed in the optical waveguide 12. The reflector 16 is adapted to transmit an image beam IB from the display device 18 to the beam splitters 14, and the beam splitters 14 are adapted to transmit the image beam IB to a user's eyes E. When the image beam IB is transmitted within the optical waveguide 12, a part of the image beam IB (e.g., an image beam IBB) generates stray light IB2 in angle symmetry to normal outgoing light IB1 due to a travelling path change, which leads the user to view not only a normal image, but also a ghost image in symmetry to the normal image. Referring to FIG. 1B, the partial image beam IBB incident to the reflector 16 deviates from the normal travelling path of the image beam IBA due to a second reflection occurring to the reflector 16 (at a position of the second reflection marked by circle in FIG. 1B), which results in the stray light IB2 being formed subsequently and causes adverse affection to display quality. Therefore, how to reduce a ratio of the stray light has become one of the major subjects for the technology development in the art.
The information disclosed in this “Description of Related Art” section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Further, the information disclosed in this “Description of Related Art” section does not mean that one or more problems to be resolved by one or more embodiments of the invention were acknowledged by a person of ordinary skill in the art.